They will special order it for you at some of the ferreterias, but you're best serve by buying them from abroad and import them into the DR yourself. As long as the amount is not too much and the rate of transport fits the bill, you'll get them here in no time and cheaper...
I did that with some bathroom glass panels we wanted some years back with the shipping company being the only one paid for the services and transport to our own door in Santiago.
Santo Domingo is a nice place and this is a very good Mall that have many services, parking is the main part of a mall. My friend told me about this place and it's beauty. He stayed here for business.